An automatic programming system is available in which a dialog display and a function key (soft key) display are each presented in accordance with each step of a plurality of data input step. In such a method a function key (soft key) conforming to a specific function and appearing on the function key display is pressed to thereby execute processing corresponding to the function, and an NC program for turning is prepared using data inputted while referring to the dialog display.
An automatic programming system of this kind, which will be described with reference to FIG. 12, successively displays predetermined message images (the dialog display) on a display screen in accordance with the following steps:
(1) a first step of selecting execution of "AUTOMATIC PROGRAMMING";
(2) a second step of selecting data to be inputted (a step to be executed next);
(3) a third step of selecting the material of a blank;
(4) a fourth step of setting surface roughness;
(5) a fifth step of selecting a drawing format;
(6) a sixth step of inputting the blank profile and the dimensions thereof;
(7) a seventh step of inputting a part profile and the dimensions thereof;
(8) an eighth step of inputting the machining reference point and turret position;
(9) a ninth step of selecting a machining process;
(10) a tenth step of selecting a tool and inputting tool data;
(11) an eleventh step of deciding machining conditions;
(12) a twelfth step of inputting cutting direction;
(13) a thirteenth step of inputting cutting limits;
(14) a fourteenth step of inputting whether or not an area is to be cut by the same tool; and
(15) a fifteenth step of computing a tool path (i.e. of preparing NC data).
An operator responds to the messages by entering the necessary data from a keyboard. Finally, an NC program (NC data) for turning is created using all of the entered data.
Accordingly, when a slot shape is entered at the part profile input step (seventh step) and data for machining the slot are entered at the machining processing input step (ninth step), an NC program of a tool path (P.sub.s .fwdarw.P.sub.1 .fwdarw.P.sub.e) for machining a slot SLT from a starting point P.sub.s to an end point P.sub.e shown in FIG. 13(a), by way of example, is created at the 15th step of computing a tool path (NC program creation).
There are cases where a slot SLT having a great width as shown in FIG. 13(b) is machined. In such cases, the conventional automatic programming method is such that, after cutting is performed over a cutting depth d from the starting point P.sub.s to the point P.sub.1, the tool TL is raised to the point P.sub.s in rapid-traverse, the tool is then fed longitudinally of the blank by an amount w corresponding to tool width and the same machining is performed from a point P.sub.2, after which the foregoing is repeated up to the end point P.sub.e. Thus, a tool path is decided in such a manner that the foregoing grooving will take place. When machining is thus performed down to the deepest part of a slot by the tool width according to the conventional method, the tool TL is raised to the outside of the slot SLT and is shifted by the amount of the tool width, after which a neighboring portion is machined.
Consequently, when the slot SLT to be machined has a large width and depth, a long period of time is needed for cutting and the actions for raising the tool out of the slot increase in number, as a result of which machining time increases correspondingly.